Container with pouring lip



1963 D. J. CRAWFORD ETAL 3,

CONTAINER WITH POURING LIP Filed June 22, 1961 INVENTORS .& J4Ms (MnF020 &

BY V/lvce/vr A'esu/vm/v 47/44., M w. 42.0w

United States Patent Ollice lifillbfid Patented Dec. 31, 1963 3,116,002CGNTAENER WHTH POURKNG Lil? Duncan James Crawford, Franklin, and VincentA i-slanian, Farmington Township, Galrland County, Mich, assignors tolix- Cell-t) Corporation, Detroit, Mich, a corporation oi Michigan FiledJune 22, 1961, Ser. No. 118,8b7 4 Claims. (Cl. 229-17) This inventionrelates to containers made of thermoplastic or thermoplastic-coatedpaperboard sheet material and having closures which include a pouringlip sanitarily protected therein. More particularly, the inventionrelates to a container of the character set forth and to an improvedcomposition for rendering the pouring lip area non adherent to thethermoplastic materials utilized to seal the container closure.

In the packaging of fluids such as milk and other dairy products,extensive use is made of containers formed of paperboard sheet materialhaving an overall coating of thermoplastic film such as polyethyleneapplied on the surfaces of the sheet. This plastic coated paperboard isimpervious to moisture and is particularly suitable for use in packagingacidic products of which milk and orange juice are illustrative. Thethermoplastic coating not only serves to moistureproof the container butalso can be utilized for sealing the container closure flaps. Thissealing action is accomplished by heating the surfaces to be sealed andquickly pressing them tightly together to form a liquid ti htplastic-toplastic bond.

In many such containers a spout having a pouring lip is enclosed withinthe closure portion of the container. When the container is sealed, thesanitary integrity of the pouring lip is preserved until the containeris opened. When the paperboard blank from which the container is formedis initially prepared, all of the surfaces of the container are coatedwith the thermoplastic material. The pouring is thus also coated and, inthe event heat is applied directly to the lip surfaces, the lip itselfbecomes tightly sealed within the closure. When such a container isopened, the lip is apt to become damaged, resulting in objectionableoperation and presenting an unsightly appearance.

One obiect of the present invention is to provide, for use with acontainer of plastic coated paperboard having a pouring lip sanitarilyhoused within a sealed closure, an improved sealing resistantcomposition for protecting the pouring lip from being permanently andinaccessibly scaled within the closure.

Another object of the present invention is to provide an improvednon-sealing adhesive composition for use in protecting the pouring liparea of a container closure to prevent the lip from being permanentlysealed when the container closure is sealed.

A further object of the present invention is to provide an improvedsealing resistant adhesive coating composition for protecting thepouring lip of a plastic coated paperboard container which does notinterfere with the closing and sealing of the container closure andwhich imparts excellent release and non-stick characteristics to thislip.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds taken in connection withthe accompanying drawings wherein:

FIGURE 1 shows an illustrative container having an enclosed pouringspout to which the present invention has been applied.

FIG. 2 illustrates the container shown in FIG. 1 during a preliminarystep of opening the container to eX- pose the pouring spout.

FIG. 3 illustrates a container of the type shown in FIG. 1 with thepouring spout opened and the pouring lip in position for dispensing thecontainer contents.

MG. 4 a fragmentary portion of the inside surface of a flat blank ofplastic coated paperboard material from which the container shown inFIG. 1 can be erected.

FIG. 5 is a View similar to FIG. 4 but illustrating the outsidecontainer surface of the blank.

While certain illustrative forms of the present invention have beendescribed below in considerable detail, and an illustrative use shown inthe drawing, it should be understood that there is no intention to limitthe invention to the specific form disclosed. On the contrary, theintention is to cover all modifications, alternative constructions,equivalents and uses falling within the spirit and scope of theinvention as expressed in the appended claims.

One container of the type with which the present invention findsparticular, but not necessarily exclusive utility, is shown in theaccompanying drawing. Such a container is also disclosed in considerablygreater detail in cop-ending Egleston and Monroe application, Serial No.707,259, filed ianuary 6, 1958, now abandoned. For present purposes,however, it will sufilce to note that such container may be formed frompaperboard or other appropriate foldable sheet material and is selfsustaining in shape. The sheet material is rendered liquid tight as bymeans of an overall coating, on both surfaces, of a thermoplasticmaterial such as polyethylene, making the container capable of holdingsuch acidic liquids as milk and orange juice. This thermoplastic coatingalso serves as a heat sensitive adhesive by which overlapping layers ofthe sheet material may be sealed together when erecting and sealing thecontainer. The coating adheres tightly to the paperboard so that it, aswell as any seals utilizing the coating, remains permanent and liquidtight.

Referring more specifically to FIGURE 1, there is shown an illustrativecontainer C of the character set forth above and formed of plasticcoated paperboard. The container comprises a tubular body 20 ofgenerally rectangular cross section, having a flat bottom closure 21 anda top closure 22, which will be recognized as the familiar gable topclosure characterized by inclined roof panels 24, 25, surmounted by anupstanding central sealing rib or truss 26. In the present instance, thepaperboard from which the container is formed is coated withpolyethylene film, the coating being about 0.75 mil thick on the outercontainer surface and about 1.5 mil thick on the inner surface.

The gable top closure is formed by the inclined roof panels 24, 25 eachof which is surmounted by an outer sealing rib panel 29, 3%, togetherwith a pair of iii-turned triangular end panels 31, 32 each joined tothe adiacent roor panels 24 25 by triangular fold-back panels 34, 35 and36, 37, respectively. A side seam flap 38 is provided at one edge of theblank for the container C,

for jointlcr with roof panel 2d and its associated side and bottompanels, to complete the body of the container. To complete the sealingrib, each of the triangular fold-back panels includes adjacent its upperedge a corresponding one of inner rib panels 3-), 40, 41, 42. Thesepanels are shown more clearly in FIGS. 4 and 5 which illustrate a layoutof a blank adapted to be erected into the completed container andclosure of FIG. 1. Vlhen a container is erected from such a blank, theside seam flap 33 is first attached to the opposite edge portion of theblank to produce a flat-folded tube. This fiatfolded tubular blank maybe erected in any manne known in the art to form a container andclosure. In a completed closure of the type shown, the rib panels areall laminated together, with the inner rib panels 39, 40, 41, 42 foldedbetween the outer rib panels 29, on the inclined roof panels. To sealthe closure, heat is applied to the thermoplastic coating on the variousrib panels just before the container is closed, after which a sealingpressure is applied to the sealing rib or truss thus formed by thevarious rib panels so that the hot plastic on contacting rib surfacesfuses to form a liquid tight sanitary seal.

In order to dispense the contents of the container C, a suitable openingor spout is accessibly provided as a part of the closure. For example,in the case of a gable top closure as shown in FIGS. 1 and 2, one orboth of the ends of the closure may be adapted to be pulled out to forma pouring spout 44 as illustrated in FlGS. 2 and 3. This is readilyaccomplished by separating the portions of the rib 26 above one endpanel 31 with opposed thumb pressures applied to the adjacent fold-backpanels 34, 35 and then snapping the end panel 3i and the two adjacentfold-back panels 34, 35 out from between the inclined roof panels. Thecontents can then be poured from the container by utilizing these panelsand their associated rib panels 3?, 4-0 as a spout 44 in which the freeedge portions of the rib panels 39, 40 serve to define a pouring lip 45.

When the closure is heated and subjected to pressure to effect a sealand thereby provide a sanitary package, all of the rib panels aresubjected to heat at a temperature suficiently high to render thethermoplastic coating on the container molten or tacky so as to effect aliquid tight seal when the container closure elements are pressedtogether. Because the thermoplastic material forms an extremely tightbond, provision must be made in the structure of the top closure sealingrib 26 to render the pouring spout accessible to the user after theclosure has been scaled. However, by placing a heat and sealingresistant material 46 over the pouring lip area, as disclosed incopending application Serial No. 707,259, supra, the lip itself is notpermanently bonded to the other parts of the closure although it iscompletely and sanitarily sealed within the closure. With such a sealingresistant material, hereinafter referred to as an adhesive, on thepouring lip area, it is a simple matter to open the closure and expose aspout having a smooth, undamaged, sanitary pouring lip.

In carrying out the present invention, selected areas of the spoutsurfaces adjacent the pouring lip and those other rib surfaces whichcontact the lip area in the completed closure are coated or treated withan improved abhesive, comprising essentially a high molecular weightorgano-siloxane gum containing primarily dimethyl siloxane polymers ofthe general formula (Ql-l SiO Such siloxane gums have a molecular weightabove 150,000, and usually in the range of 150,000-250,000. These gumcompositions are capable of being cured or cross-linked, and for thispurpose there is added a small amount of monomethyl or methyl hydrogensiloxane polymers, together with suitable catalysts such as the metalsalts of carboxylic acids. For example lead, iron, Zinc, or cobalt saltsof acetic, hexoic or octoic acids.

The siloxane gum composition is applied in a dilute organic solventsolution such as a xylene or toluene solution, as a coating on the lipof the pouring spout and adjacent rib areas, in this instance shown asthe she. ed areas 46, 4'7, 49 in the drawings, where it is desired toavoid permanent sealing. Uncoated marginal sealing areas are left aroundthe adhesive areas for use in sealing the container. These siloxane gumsemployed are of a type generally known in the art and are described byRochow in Chemistry of the Silicones, 2d ed, lohn Wiley & Sons, lnc.,New York, 1951 (p. 94), and the references cited therein, such as US.Patent No. 2,448,556.

The particular amount of siloxane applied as an adhesive coating is notcritical. Satisfactory results have been achieved by applying thesolution with conventional inking or gluing equipment, e.g. fiexographicprinting equipment, in a layer about 0.0001 inch thick over the areas tobe protected. The siloxane adhesive is applied from a solvent solution,and after the application the treated surfaces are allowed to dry.Solvent removal may be facilitated by mild heating.

One polysiloxane gum composition found to be useful as an adhesive onthe pouring lip of a polyethylene coated container had the followingcomposition:

A 30% solution in xylene of the following gum:

Parts by weight Dirnethyl polysiloxane 97%, M.W. 222,000; methylhydrogen polysiloxane 3%, visc. centistokes A preferred solution of theadhesive composition is given above. In practice, it has been found thatbetween about 5 and about 15 parts by weight of the 30% xylene solutioncan be employed so long as the final solution is of a viscosity suitablefor application by printing or other method which may be employed. Thegum solution was then applied as a thin coating about 0.0001 inch thickto selected areas of the lip forming ribs 39, 40 (area 46) of a blank asshown in FIGS. 4 and 5, and to adjacent ribs 29 and 30 (areas 48 and4-0) by a fiexographic printer, leaving uncoated marginal sealing areas.The blanks were allowed to dry and were subsequently erected, filled andheat sealed in a conventional manner to produce a container like thatshown in FIG. 1.

When a container formed from a blank to which the above describedadhesive was opened to expose the pouring spout, the sealing rib wasreadily separated as shown in FIG. 2, and when the spout was extended(FIG. 3) the pouring lip was smooth and undamaged and was ready for use.

It will, of course, be appreciated by those skilled in the art that thepresent invention is not limited to use on containers of polyethylene orpolyethylene-coated paperboard. For example, the method of the presentinvention may be satisfactorily applied to containers made of or coatedwith other plastic materials such as polypropylone, rubber hydrochloridepolymers, polyvinyl chloride, polyvinyl acetate copolyrners, and likepolymeric substances.

We claim as our invention:

1. In a dispensing container having a tubular body surmounted by asealed closure sanitarily housing a pouring lip, said closure and lipbeing formed of sheet material having a heat scalable thermoplasticsurface with a sealing resistant coating applied over said surface atsaid lip, the improvement wherein said sealing resistant coatingcomprises a polysiloxane gum.

2. A dispensing container as defined in claim 1 wherein said sealingresistant coating comprises dimethyl polysiloxane gum.

3. A dispensing container as defined in claim 1 wherein said sealingresistant coating comprises dimethyl polysiloxane gum and a small amountof methyl hydrogen polysiloxane.

4. In a dispensing container having a body surmounted by a sealedclosure sanitarily housing a pouring lip, said body, closure and lipbeing formed of paperboard sheet material having an overall polyethylenecoating with a sealing resistant coating applied over said polyethylenecoating at said lip, the improvement wherein said sealing resistantcoating comprises a polysiloxane gum which is References Cited in thefile of this patent resistant to sticking to said polyethylene coatingwhen the 10 2,985,545

closure is heat sealed.

UNITED STATES PATENTS Alfred Apr. 12, 1938 Boysen Nov. 16, 1943Sidebotham Nov. 14, 1944 Hood July 31, 1951 Dixon Nov. 30, 1954 LeavittMay 23, 1961 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No 3,116,002 December 31, 1963 Duncan James Crawford et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below Column 1, lines 52 and 57 column 3 line 56, and column4, lines 6, l3 and 14. l8 23. 33 and 4L9 for "adhesive'fl eachoccurrence read abhesive Signed and sealed this 26th day of May 1964(SEAL) Attest:

ERNEST w; SWIDER EDWARD J. BRENNER Altesting Officer Commissioner ofPatents

1. IN A DISPENSING CONTAINER HAVING A TUBULAR BODY SURMONTED BY A SEALEDCLOSURE SANITARILY HOUSING A POURING LIP, SAID CLOSURE AND LIP BEINGFORMED OF SHEET MATE-